Stwart Peña Feliz, Co-founder and CEO of MacroCycle Technologies, Is Taking a Different Route to Circular Plastics
Published: 2026 | Author: VisionariesNetwork Team
Plastic recycling has spent years trying to solve a difficult equation: how to recover useful materials from waste without making the process so expensive, energy-intensive, or complicated that it becomes difficult to scale. For Stwart Peña Feliz, Co-founder and CEO of MacroCycle Technologies, the answer lies not simply in recycling more plastic, but in reconsidering the chemistry behind how polymers are recovered in the first place.
MacroCycle is developing technology designed to transform difficult waste streams, particularly polyester textiles, into high-quality polyester resin. The Cambridge, Massachusetts-based company says less than 1% of textiles are recycled each year, while conventional mechanical recycling has difficulty handling mixed and contaminated textile waste. Its approach is intended to address that gap by working with real-world waste rather than relying solely on clean, uniform feedstock.
For Peña Feliz, the problem is closely connected to his own professional experience. Before becoming an entrepreneur, he worked as a process engineer at ExxonMobil, gaining experience in manufacturing, process design, and the operation of large-scale industrial units. His background also included work involving plastic pyrolysis, giving him an understanding of what it takes to move chemical processes beyond laboratory experiments and into industrial environments. He later earned an MBA from MIT Sloan School of Management, where his path crossed with MacroCycle co-founder and CTO Jan-Georg Rosenboom.
That combination of engineering and business experience has become particularly relevant to MacroCycle's ambitions. Deep-tech companies often face a difficult transition between proving that a scientific concept works and demonstrating that it can operate reliably, economically, and at meaningful scale.
Peña Feliz brings experience in that space, having previously scaled technologies from the bench level and held leadership positions at a climate-tech startup that later raised a $30 million Series B round. His role at MacroCycle is therefore not limited to the commercial side of the business. His engineering background gives him a practical perspective on how a promising chemical process needs to function outside the laboratory.
A Different Chemistry for Textile Waste
MacroCycle's technology is called SolvoGenesis™, a proprietary process based on solvent systems and macrocyclic chemistry. Rather than approaching recycling primarily by breaking polymer bonds apart, the company describes its process as one that creates new bonds, bringing waste polymers into a form that can be used to produce high-quality polyester materials.
The distinction is important because polyester waste can come in many forms. Clothing and other textile products may contain blends, dyes, finishes, additives, and other materials that make straightforward recycling difficult. MacroCycle says its process is designed to handle polyester waste in a wider range of conditions, with the company targeting waste streams containing more than 50% polyester. Its stated objective is to turn that material into virgin-quality polyester rather than a lower-value recycled product.
The company currently highlights two product directions. MacroTEX™ is focused on producing 100% polyester from textile waste, while MacroPACK™ is designed to produce virgin-grade PET resin for plastic bottles using end-of-life textiles as the source material. This creates a potential connection between textile recycling and applications beyond apparel, giving recovered polyester another route into the manufacturing economy.
MacroCycle's work has also attracted attention from the wider climate-tech and entrepreneurship ecosystem. The company announced a $6.5 million seed round to commercialize its plastic upcycling technology, while MIT has highlighted the company's process as consuming substantially less energy than traditional approaches. MacroCycle has also received an NSF SBIR Phase I grant and has developed relationships across the textile, plastics, research, and climate-tech communities.
From Industrial Engineering to Entrepreneurship
Peña Feliz's transition from a major industrial company to an early-stage climate-tech venture reflects a broader shift in his career. His experience at ExxonMobil gave him exposure to the realities of operating industrial processes, while MIT Sloan provided an environment in which technical ideas could be examined through a business and entrepreneurial lens.
The meeting with Rosenboom became an important turning point. MacroCycle's story began at MIT, where the two co-founders brought together Rosenboom's expertise in chemistry with Peña Feliz's process engineering and operating experience. The company says that combination helped shape a technology intended not only to work scientifically but also to address the practical requirements of commercialization.
Peña Feliz has since emerged as a visible voice in the circular-plastics space. His work has been recognized through Forbes' 30 Under 30 list for Manufacturing & Industry, while MacroCycle continues to expand its technology and team in Cambridge. The company's current team includes specialists in polymer chemistry, analytical chemistry, extrusion engineering, operations, partnerships, and AI solutions, reflecting the multidisciplinary nature of the challenge it is tackling.
Making Circularity Practical
For MacroCycle, the larger ambition is not simply to keep more textiles away from disposal. It is to create a system in which polyester can remain in productive use rather than repeatedly requiring new raw materials. The company describes this as a fully circular approach, with a focus on producing materials that can compete with conventional polyester on quality and cost.
That ambition places Peña Feliz at the intersection of engineering, entrepreneurship, and climate technology. His experience gives him an appreciation for the gap between an idea that works in a controlled environment and a process that can operate at industrial scale. At MacroCycle, that perspective is being applied to one of the less visible challenges in the circular economy: making textile waste useful again.
As MacroCycle advances its SolvoGenesis™ technology and develops applications for both textiles and packaging, Peña Feliz's role is to connect the scientific promise with the realities of manufacturing, commercialization, and scale. The company's progress suggests that the future of recycling may depend not only on collecting more waste, but also on finding smarter ways to turn that waste back into materials that industry can use.
“Turning difficult plastic waste into valuable materials requires more than innovative chemistry; it requires the engineering discipline to make that innovation work at scale.”
FAQs
1. Who is Stwart Peña Feliz?
Stwart Peña Feliz is the Co-founder and CEO of MacroCycle Technologies. He is a former ExxonMobil process engineer with experience in manufacturing, process design, and large-scale industrial operations.
2. What is MacroCycle Technologies working on?
MacroCycle Technologies is developing recycling technology that converts difficult polyester waste, including textile waste, into high-quality polyester materials that can be used again.
3. What is Stwart Peña Feliz’s professional background?
Before co-founding MacroCycle, Peña Feliz worked as a process engineer at ExxonMobil. He has experience scaling technologies from bench scale and has also held leadership roles at a climate-tech startup. He holds an MBA from MIT Sloan School of Management.
4. How does MacroCycle’s technology approach plastic recycling?
MacroCycle uses its SolvoGenesis™ process to work with polyester waste and recover it as high-quality material. The technology is designed to address waste streams that can be difficult for conventional mechanical recycling methods to handle.
5. What products is MacroCycle developing?
MacroCycle is developing MacroTEX™, which focuses on producing polyester from textile waste, and MacroPACK™, which targets virgin-grade PET resin for packaging applications using end-of-life textiles as a feedstock.
Browse our most recent publications
